Storage caches are widely used in storage systems for improving input/output (I/O) latency and I/O throughput. Traditionally, caches were implemented solely in memory (e.g., a random access memory (RAM) or another volatile storage). Today, non-volatile flash-based devices, such as solid-state drives (SSDs), increasingly are used as caching layers, where flash-based caches are implemented and managed indistinguishably from memory caches. However, flash-based solid-state drives and volatile storage devices have different characteristics and tradeoffs with respect to performance, reliability and capacity.
For example, erase-and-write cycles impact the lifetime of flash-based caches differently than memory. In typical cache algorithms, when there is a cache hit, data is read from the cache, and when there is a cache miss, data is written to the cache. As each cache fill involves an erase-and-write cycle, each cycle on a cache implemented on a flash-based solid-state drive has a significant impact on the lifespan of the flash-based solid-state drive.